The New York Times ran an article maybe 5 years ago about the cell division of a fetus. There are only two types of cells, at least at first: cells that become bone and muscle and cells that become hair, nails, and brain. So, I take Ultra Hair Thick shake for my hair, nails and brain. It tastes great and I have almost no grey hair at age 59.

I have Barrets Esophagus... damage to my esophagus that left ore-cancerous cells growing in my esophagus. This product created an intense pain in my esophagus that felt as if I had poured acid into down my throat. The pain lasted a long time. I called Life Extension about it and they advised me to try it again in case there was something wrong with the 1st dose. Bad idea! It was just as painful the 2nd time.
If you already have Barrets I suggest stearing clear of thus product.

As an essential amino acid, lysine is not synthesized in animals, hence it must be ingested as lysine or lysine-containing proteins. L-Lysine is a necessary building block for all protein in the body. L-Lysine plays a major role in calcium absorption; building muscle protein; recovering from surgery or sports injuries; and the body's production of hormones, enzymes, and antibodies. It has been suggested that lysine may be beneficial for those with herpes simplex infections.